The influence of isometric preload on power expressed during bench press in strength-trained men     

Sandro Bartolomei  David H. Fukuda  Jay R. Hoffman  Jeffrey R. Stout  Franco Merni 《European Journal of Sport Science》2017,17(2):195-199

The purpose of this study was to compare the power expressed during the bench press exercise in resistance-trained men following different pre-activation conditions. Twenty-two trained men (age 24.1?±?1.7 years, height 178.6?±?6.1?cm, body mass 81.1?±?10.6?kg) completed a maximal effort bench press (1-RM) test (100.0?kg?±?8.1?kg). In a subsequent assessment, each participant performed concentric bench press movements with loads of 20%, 30%, 40% and 50% of their 1-RM preceded by either a concentric contraction (CC), a low isometric preload (LIP; 70% 1-RM) or a high isometric preload (HIP; 100% 1-RM) conditions. All movements were performed in a Smith machine with a settable quick-release device. Participants performed all three conditions in randomized fashion. Results indicated that power outputs during the bench press exercise following HIP were significantly (p?<?0.05) greater than CC at 20% 1-RM (+9%), 30% 1-RM (+16%) and 40% 1-RM (+14%), and LIP at 20% 1-RM (+4%), 30% 1-RM (+20%) and 40% 1-RM (+15%). No differences were found between conditions at 50% 1-RM. Area under the force–power curve with HIP was greater (p?<?0.05) than with CC and LIP. In conclusion, results of this study indicate that the use of a HIP (100% 1-RM) in trained participants results in significantly greater power output during the concentric phase of a multi-joint exercise when compared to standard concentric movement.  相似文献   

Multiple-joint exercises using elastic resistance bands vs. conventional resistance-training equipment: A cross-over study     

Vegard M. Iversen  Paul Jarle Mork  Ottar Vasseljen  Ronny Bergquist  Marius S. Fimland 《European Journal of Sport Science》2017,17(8):973-982

Previous studies indicate that elastic resistance bands (ERB) can be a viable option to conventional resistance-training equipment (CRE) during single-joint resistance exercises, but their efficacy has not been established for several commonly used multiple-joint resistance exercises. Thus, we compared muscular activation levels in four popular multiple-joint exercises performed with ERB (TheraBand^®) vs. CRE (Olympic barbell or cable pulley machines). In a cross-over design, men and women (n?=?29) performed squats, stiff-legged deadlifts, unilateral rows and lateral pulldown using both modalities. Multilevel mixed-effects linear regression analyses of main and interaction effects, and subsequent post hoc analyses were used to assess differences between the two resistance-training modalities. CRE induced higher levels of muscle activation in the prime movers during all exercises (p?<?.001 for all comparisons), compared to muscle activation levels induced by ERB. The magnitude of the differences was marginal in lateral pulldown and unilateral rows and for the erector spinae during stiff-legged deadlifts. In squats the quadriceps femoris activations were substantially lower for ERB. The differences between ERB and CRE were mostly observed during the parts of the contractions where the bands were relatively slack, whilst the differences were largely eliminated when the bands became elongated in the end ranges of the movements. We conclude that ERB can be a feasible training modality for lateral pulldowns, unilateral rows and to some extent stiff-legged deadlifts, but not for the squat exercise.  相似文献   

L2 Willingness to Communicate and Perceived Accent Strength: A Qualitative Inquiry     

Nourollah Zarrinabadi  Ensieh Khodarahmi 《Journal of Intercultural Communication Research》2017,46(2):173-187

This study examined whether and how English as a foreign language (EFL) learners` perceptions towards their own and others` accent is liable to impact their second language (L2) willingness to communicate (WTC). The content analysis of interviews with 20 EFL learners showed that L2 WTC was amenable to their hegemonic attitudes towards native English accents. As many as four recurring themes arose from the interviews which showed how perceived accent strength can impact L2 WTC. These include: Accent-related stigmas, accent-based disruptiveness, aspiration for showing off one`s accent, and self-perceived communicative competence and self-confidence. The paper concludes by discussing the implications of the findings and outlining avenues for future research.  相似文献   

Association of physical fitness,body composition,cardiometabolic markers and adherence to the Mediterranean diet with bone mineral density in perimenopausal women. The FLAMENCO project     

Virginia A. Aparicio  Pilar Ruiz-Cabello  Milkana Borges-Cosic  Ana Andrade  Irene Coll-Risco  Pedro Acosta-Manzano 《Journal of sports sciences》2017,35(9):880-887

This study aimed to analyse the association of different components of physical fitness, body composition, cardiometabolic markers and the Mediterranean diet with bone mineral density (BMD) in perimenopausal women, and to test which of these components are independently associated with BMD. The sample comprised 197 perimenopausal women (52.6 ± 4.5 years). Physical fitness was assessed with the “Senior Fitness Test” battery and the handgrip strength and Bruce tests. Fat and lean mass and BMD were measured using dual-energy X-ray absorptiometry. We analysed the markers of metabolic syndrome, C-reactive protein, and components of the Mediterranean diet. Handgrip muscle strength (β = 0.212, P = 0.005), body weight (β = 0.244, P = 0.001), BMI (β = 0.180, P = 0.011) and lean mass (β = 0.379, P < 0.001) were positively associated with BMD. No associations were observed between cardiometabolic markers or the Mediterranean diet with BMD (all P > 0.05). When all relevant indicators of BMD were simultaneously considered, lean mass was the only 1 showing an independent association with BMD (β = 0.392, P < 0.001), explaining 14% of the BMD variability. In conclusion, muscle strength might be a marker of BMD in perimenopausal women. However, lean mass was the only factor independently associated with BMD. Future research to determine whether increasing lean mass through specific exercise-based interventions contributes to increasing BMD is warranted.  相似文献   

新型太极拳干预对老年女性膝骨关节炎患者          下载免费PDF全文

潘晓雨  黄灵燕  吕娇娇  伍勰  牛文鑫  刘宇 《体育科研》2017,(1):68-71

目的：验证6个月的新型太极拳康复方案干预是否可以改善老年女性膝关节炎患者的下肢肌力和动态平衡能力。方法：招募46名老年女性膝骨关节炎患者，随机分为太极组和对照组，进行为期6个月的实验干预。实验前后，通过等速肌力测试仪和动态平衡测试指标，测量所有受试者下肢肌力和动态平衡能力。结果：6个月前后，太极组下肢肌力无显著性差异（P>0.05），但动态稳定性显著性提高（P<0.05）。结论：新型太极拳康复干预可促进女性膝骨关节炎患者动态平衡稳定性，简易有效，易于推广。  相似文献   

The effects of high resistance–few repetitions and low resistance–high repetitions resistance training on climbing performance     

Espen Hermans  Vidar Andersen 《European Journal of Sport Science》2017,17(4):378-385

The aim of the study was to compare the effects of different strength training intensities on climbing performance, climbing-specific tests and a general strength test. Thirty lower grade and intermediate-level climbers participated in a 10-week training programme. The participants were randomized into three groups: high resistance–few repetitions training groups (HR-FR), low resistance–high repetitions training groups (LR-HR) and a control group (CON) which continued climbing/training as usual. Post-testing results demonstrated statistical tendencies for climbing performance improvements in the HR-FR and LR-HR (p?=?0.088–0.090, effect size?=?0.55–0.73), but no differences were observed between the groups (p?=?0.950). For the climbing-specific tests, no differences were observed between the groups (p?=?0.507–1.000), but the HR-FR and LR-HR improved their time in both Dead-hang (p?=?0.004–0.026) and Bent-arm hang (p?<?0.001–0.002). The HR-FR and LR-HR improved their 12RM strength in pull-down (p?≤?0.001), but not the CON group (p?=?0.250). No differences were observed in the CON group in any of the tests (p?=?0.190–0.596) with the exception of improvement in Bent-arm Hang (p?=?0.018). The training groups reduced their climbing sessions during the intervention compared to the CON group (p?=?0.057–0.074). In conclusion, HR-FR and LR-HR training programmes demonstrated an 11% and 12% non-significant improvement in climbing performance despite a 50% reduction in climbing sessions, but improved the results in strength and climbing-specific tests. None of the training intensities was superior compared to the others.  相似文献   

Physical requirements in Olympic sailing     

J. Bojsen-Møller  B. Larsson  P. Aagaard 《European Journal of Sport Science》2015,15(3):220-227

Abstract

Physical fitness and muscular strength are important performance parameters in Olympic sailing although their relative importance changes between classes. The Olympic format consists of eight yacht types combined into 10 so-called events with total 15 sailors (male and female) in a complete national Olympic delegation. The yachts have different requirements with respect to handling, and moreover, each sailor plays a specific role when sailing. Therefore physical demands remain heterogeneous for Olympic sailors. Previous studies have mainly examined sailors where ‘hiking’ (the task of leaning over the side of the yacht to increase righting moment) is the primary requirement. Other than the ability to sustain prolonged quasi-isometric contractions, hiking seems to require significant maximal muscle strength especially in knee extensors, hip flexors and abdominal and lower back muscles. Another group of studies has investigated boardsailing and provided evidence to show that windsurfing requires very high aerobic and anaerobic capacity. Although data exist on other types of sailors, the information is limited, and moreover the profile of the Olympic events has changed markedly over the last few years to involve more agile, fast and spectacular yachts. The change of events in Olympic sailing has likely added to physical requirements; however, data on sailors in the modern-type yachts are scarce. The present paper describes the recent developments in Olympic sailing with respect to yacht types, and reviews the existing knowledge on physical requirements in modern Olympic sailing. Finally, recommendations for future research in sailing are given.  相似文献   

振动波方向影响肌肉振动训练效果的实验研究     

刘北湘  周瑾  刘晓亚  李家发  戴玮 《成都体育学院学报》2015,(2):100-105

文章主要研究在不同振动波条件下对肌肉力量训练效果的影响。以33名大学男生为研究对象,在不同方向振动波的条件下进行负重蹲实验。以三维影像与三维测力台同步测量系统采集跳深和负重蹲动作的运动学及动力学数据;以瑞士等速肌力测试系统采集膝关节在不同速度时向心、离心运动的肌力学数据。分析结果认为,振动波方向影响肌肉振动训练的效果。振动波方向与肌纤维纵轴之间趋向于垂直状态或形成较大角度时,振动波能够对肌肉产生较大的刺激。振动波与肌纤维的角度过小或成平行状态时,振动波对肌肉的刺激作用便相对较小。肌纤维受到与其呈大角度的振动波的作用时间越长,便越能对肌肉能力的增强产生较大的影响。  相似文献   

“敏感期”是否对训练敏感——不同年龄段青少年力量训练效果的实验研究     

卓金源  米靖  苏士强 《北京体育大学学报》2015,38(10):139-145

摘要：通过实验的方法,选取处于最大力量素质敏感期和非力量素质敏感期的不同年龄段的青少年进行相对等量负荷的力量训练干预,观察、测试、对比不同年龄组别受试者最大力量素质增长与肌肉围度的变化情况,以探讨青少年力量素质敏感期是否对力量训练“敏感”以及不同年龄段力量增长的影响因素。本研究将实验对象分为初中、高中、大学三组（n=31）,每组实验对象进行每周2次课共为期8周的力量训练,力量练习内容包括：仰卧推举、负重背蹲。每节课持续时间为40-60分钟,力量训练负荷强度为最大强度60%-80%,重复次数为8-10次,组间歇时间为3-5分钟。在经过8周的力量训练之后,初中组的仰卧推举和负重背蹲分别提高了33.1%、32.4%;高中组的仰卧推举和负重背蹲分别提高了36.8%、28.6%;大学组的仰卧推举和负重背蹲分别提高了34.8%、29.5%,三组受试者力量素质的提高均具有显著性的差异（P<0.01）。分别对初中、高中和大学三组受试者的仰卧推举与负重背蹲在力量训练后所提高的值进行单因素方差检验,结果显示这三组数据之间不具有显著性的差异（P＞0.05）,即初中、高中和大学三组受试者的力量素质提高的幅度相近。初中、高中、大学三组受试者力量训练前后肌肉围度有一定程度的增长,但三个组肌肉围度的变化均不具有显著性的差异（P>0.05）。在有限的样本条件下,发现经过8周相对等量负荷的力量训练,处于力量素质敏感期的实验组与非力量素质敏感期的对照组力量增长的水平是相近的,即在青少年力量素质敏感期进行力量训练并不会使得力量素质获得额外的提高。  相似文献   

不同非稳定支撑面上徒手练习动作核心区肌肉肌电分析     

岳建军  龚俊丽  周燕 《北京体育大学学报》2015,38(9):52-57

摘要：目的：比较俯卧撑、仰卧起坐和俯卧转体180°3种徒手练习动作分别在地板、BOSU球、瑞士球和平衡板4种支撑面上的运动员核心区肌肉肌电数值差别,探讨稳定与非稳定练习对相关肌群刺激程度,重新认识核心训练的实质,为核心稳定性训练手段的优化提供依据。方法：以15名高水平健美操运动员为研究对象,运用Noraxon 公司的Telemyo2400DTS16通道表面肌电系统对4种支撑面上3种常用练习动作的核心区肌肉肌电数据进行分析。结果：运动员在完成仰卧起坐练习时只有在地板上竖脊肌积分肌电值有显著性差异（P<0.05）。俯卧撑练习时BOSU球与瑞士球、地板与瑞士球、平衡板与瑞士球相比,腹直肌的积分肌电值有显著性差异（P<0.05）,其中后2种相比腹斜肌积分肌电值有非常显著差异（P<0.01）; 胸大肌积分肌电值地板与BOSU球相比有非常显著性差异（P<0.01）,地板与瑞士球相比有显著性差异（P<0.05）。俯卧转体180°练习时,只有腹斜肌和竖脊肌积分肌电值在地板与瑞士球、地板与平衡板上呈现非常显著性差异（P<0.01）,BOSU球与瑞士球相比呈现显著性差异（P<0.05）。结论：在选择核心区力量训练手段时,仰卧起坐动作适宜在稳定支撑面上进行;俯卧撑和俯卧转体动作适宜在瑞士球上进行。因此,核心非稳定训练并不一定比稳定训练对肌肉有更强烈的刺激,取决于所选择练习动作和器材的组合,其实质是创设核心区肌肉共同协调收缩的环境,以提高人体的稳定性。  相似文献